(I) Field of the Invention
The present invention relates to a Stirling cycle device which can be used for refrigerating or cooling in all industrial fields of industrial apparatuses of food distribution, environmental test, medicine, biological industry, semiconductor manufacture, and the like, or household apparatuses.
(ii) Description of the Related Art
In recent years, a Stirling cycle refrigerator, hereafter referred to generallt as "refrigerator", has been highlighted as a refrigerating device using a substitute for Freon in earth environmental problems, or as a refrigerator whose operation temperature is in a broader range than that of a conventional cooling device. Therefore, the refrigerator can be applied to the apparatuses utilizing cooling heat for business or household use such as a freezer, a refrigerator, and a throw-in type cooler, and the cooling heat utilizing apparatuses of all industrial fields such as a low-temperature fluid circulator, a low-temperature isothermal unit, an isothermal tank, a heat shock test device, a freezing drier, a thermal property test device, a blood/cell storage-device, a cold cooler, and other various cooling heat devices. Furthermore, the refrigerator is compact, high in result coefficient, and excellent in energy efficiency.
FIG. 1 is an entire schematic view of a conventional general Stirling cycle refrigerator 1, and in a housing 2, crank portions 5, 6 of a crank shaft 4 operated by a motor 3 are connected to a compression piston rod 9 and an expansion piston rod 10 via cross guide heads 7, 8. Via these compression piston rod 9 and expansion piston rod 10, a compression piston 11 and an expansion piston 12 reciprocate with a phase difference in a compression cylinder 13 and an expansion cylinder 14, respectively. Thereby, operating gas is compressed and expanded. Additionally, by a radiating heat exchanger (high-temperature side heat exchanger) 18 and a cooling heat exchanger (low-temperature side heat exchanger) 19 disposed between a high-temperature chamber (compression chamber) 15 of the compression cylinder 13 and a low-temperature chamber (expansion chamber) 16 of the expansion cylinder 14 via a regenerator 17, heat exchange is performed between a radiating refrigerant and a cooling heat refrigerant, and the operating gas.
Here, there arises a problem, which is so-called oil rising, that oil or oil mist rises from a crank chamber along the piston rods 9, 10. For the oil rising, after entering the compression and expansion cylinders, the oil or oil mist adheres to inner surfaces, or is carbonized by heat so that the performance and durability of the refrigerator are remarkably deteriorated. To solve the oil rising problem, in a conventional art, the compression piston rod 9 and the expansion piston rod 10 are sealed by oil seals 20, 21.
Additionally, the oil seals are variously developed in structures and materials, but they are not necessarily sufficient in sealing performance or durability. Moreover, a roll socks type seal system has been proposed, whose durability cannot be said to be sufficient in the present situation.
Moreover, when the Stirling cycle refrigerator is operated, temperature rises, and inner pressure rises in a crank chamber 26. The pressure rise of the crank chamber applies a mechanical burden to the oil seal, and causes deterioration. There arises another problem that the pressure promotes the oil rising, and adversely affects the performance.
Moreover, the reciprocating movement of the compression and expansion pistons generates a pressure fluctuation on the side of a back surface, and adversely affects the oil seals.
An object of the present invention is to solve problems peculiar to the Stirling cycle refrigerator comprising the above-described refrigerator, and the problems of the present invention are as follows:
(1) The oil rising is prevented, long-life piston rod oil sealing bellows are realized, and the performance and life of the Refrigerator are enhanced. PA1 (2) For the pressure rise accompanying the temperature rise of the crank chamber, even when a general oil seal is employed, deterioration or oil rising cannot be prevented. Moreover, even when the oil sealing bellows are employed, inner and outer pressure differences are generated to adversely affect the bellows themselves and the performance of the refrigerator. The pressure rise accompanying the temperature rise of the crank chamber is solved by employing a buffer tank which has pressure adjusting bellows. PA1 (3) The problem of pressure fluctuation generated on the side of the back surface of the compressing or expanding piston which adversely affects the oil seal or the refrigerator performance is solved by employing the buffer tank provided with or without the pressure adjusting bellows. PA1 (4) The problem of the pressure fluctuation generated on the back surface side of the piston is solved by utilizing a space in the housing having the crank chamber. Specifically, the problem is solved by connecting the back surface side of the piston to the space in the housing having the crank chamber via an oil trapping device. In this case, a constricting device for adjusting the oil trapping device may also be used together (arranged in series for use).